This presentation on "Social Media in Emergency Response" contains slides defining social media and its relevancy to emergency response. The presentation gives an overview of popular social media websites, elaborating with statistics on Facebook and Twitter. Many emergency management groups have pages on Facebook, and twitter users were vital in assisting with emergency management information during the Mumbai Terrorist Attacks in November 2008. The presentation's goal appears to be clarifying how the emergency response community can use social media. The conclusion states that social media's relevance to emergency management creates "opportunities for social media use in every day and emergency response operations"; and that the "value is in the community collaboration and information sharing."
California Air Resources Board: http://www.arb.ca.gov/